Shounen is just a demographic, it doesn't define content. It just means the projected target audience is a specific age range, which for shounen would be around the ages of 10-20 for males. Does that mean the content has to be for that target audience specifically? No.

As an example, Anohana: The Flower We Say That Day is a shounen title. Not shoujo, not josei. Shounen. Think about that for a second.

For me I can't pick a top ten but I really like Gunslinger Girl, Gunbuster and its sequel Diebuster, Birdy the Mighty, and Cromartie High School.

Dragonball - THE ORIGINAL SHOUNEN COMEDY ACTION SERIES....it's amazing and everybody should watch it, despite DBZ's faults
Dragonball Z - You dont watch DBZ for the plot, action, or art. You watch it because you saw Dragonball and asked "what's next?"
Ranma 1/2
GTO
Mobile Suit Gundam - (but not any other Gundam, those arn't shounen anymore)
Gurren Lagann
Dragonball Z Return of Cooler
Trigun
One Piece
Hunter X Hunter AND Yu Yu Hakusho(because they're like the same thing)
Inuyasha for #10-18
Dragonball GT (But only the last few episodes, that being the second half of the Evil Dragons arc, not even the first half. 4-star introduction and beyond only)
Soul Eater
Avatar the Last Airbender (which would be higher if I didn't take the worst movie ever made into consideration)
Clannad, Air, Kanon, Clannad Afterstory, Angel Beats, any other anime EXACTLY THE SAME AS THIS ONE.
Fate/stay Night and Fate/Zero (If the sex scenes didn't happen, it's still a Shounen!)
Persona 4 the Videogame
FLCL
Baccano! not Durarara! (Durarara is product for Japanese people while Baccano is a product for Americans, THEY DO NOT OVERLAP!)
Attack on Titan (Subject to replace Inuyasha #14)
Neon Genesis Evangelion (It's more of an Anti-Shounen than a Shounen... and "anti" doesn't mean "not" it means "it hates children")
Big O
Berserk (Who would be much higher on this list if were actually a Shounen)
Guilty Crown IF you're ignoring protaganist Shu, which is reallllly hard. Otherwise this show is garbage and not on the list
Scrapped Princess
Eureka 7 (This one should be higher up, but I forgot to list it earlier)
The Slayers
Batman The Animated Series
Dragonball Z Abridged
The Melancholy of Haruhi Suzumiya
Spice&Wolf
Panty and Stocking with Garterbelt
Full Metal Alchemist: Original Gagstah
Sword Art Online (the upcoming GGO might bump this up a few spots
Studio Trigger and Kill la Kill (When combined they're totally Shounen)
The World God Only Knows is pretty good, but super-harems arn't really Shounen to me
Dragonball Z Budokai Tenkaichi 2
Darker than Black
World of Warcraft
Hajime no Ippo/Fighting Spirit!!
Escaflowne (I never finished this one)
Broken Blade
The Animaniac's
Toonami
Rurouni Kenshin
Samurai 7
Samurai Champloo
Samurai Jack
Dragonball GT(The bad episodes)
Code Geass doesn't go this low, but I don't want to fit it in anywhere

That's my list! I didn't count, but it's totally accurate with me. Take from it what you will.